As an alternative energy source to fossil fuel, solar cells capable of converting sun light to electric power have drawn attention. Examples of solar cells, which have been partially used practically at present, include solar cells using crystalline silicon substrates and thin film silicon solar cells.
As a new type solar cell, a wet type solar cell based on photo-induced electron transfer of a metal complex has been described in Patent Document 1. This wet type solar cell has a constitution in which a photoelectric conversion layer is formed between electrodes respectively formed on two glass substrates using photoelectric conversion materials and electrolyte materials. This photoelectric conversion material has an absorption spectrum in a visible light region by adsorbing a metal complex which is a photosensitizing dye on the surface of a metal oxide semiconductor. In this wet type solar cell, when light is irradiated to the photoelectric conversion layer, electrons are generated and electrons transfer to a counter electrode through an external electric circuit. The electrons transferred to counter electrode are conveyed by ions in the electrolyte and return back to the photoelectric conversion layer. Electric energy is outputted based on repetitions of such electron transfer.
However, as for a basic structure of the dye-sensitized solar cell module described in Patent Document 1, a dye-sensitized solar cell is made up by filling an electrolyte solution into between two glass substrates. Therefore, it is possible to produce a trial solar cell with a small surface area, but it is difficult to apply this solar cell to a solar cell with a large surface area such as 1 m square. That is, if in such a solar cell, the surface area of one photoelectric conversion device is enlarged, the generated current is increased proportional to the area. However, since a voltage drop in the plane direction of a transparent conductive film to be used for the electrode parts is increased, and the internal series resistance of the solar cell is increased. As a result, a fill factor (FF) in a current-voltage characteristic and a short circuit current at the time of the photoelectric conversion are lowered, resulting in a problem of decrease of the photoelectric conversion efficiency.
In order to solve such the problems, for example, in Patent Documents 2 and 3, there has been proposed a dye-sensitized solar cell module having a structure shown in FIG. 11. In the case of preparing this solar cell module, first, a porous semiconductor layer 112 and a catalyst layer 114 are alternately formed on two glass substrates 100 and 117 having transparent electrodes 111 and 118 formed in a comb-like shape by patterning, respectively. Next, an insulating adhesive is applied between the porous semiconductor layer 112 on one substrate and the catalyst layer 114 of the other substrate. Then, two opposed substrates were bonded to each other by overlaying both substrates on each other with the porous semiconductor layer 112 and the catalyst layer 114 opposed to each other and curing the insulating adhesive to form an insulating layer 115 between devices, and by filling an electrolyte solution into a gap between substrates and sealing a filling portion with a resin, a dye-sensitized solar cell module (the so-called W-type module), in which a plurality of photoelectric conversion devices are connected in series, has been prepared.
Further, in Patent Document 4, as shown in FIG. 12, there has been proposed a dye-sensitized solar cell module (the so-called Z-type module) in which a plurality of photoelectric conversion devices are connected in series by providing electrical continuity between one conductive layer 121 and the other conductive layer 128 of adjacent photoelectric conversion devices 121a, 121a through a connecting conductive layer 129. In this solar cell module, in order to prevent the corrosion of the connecting conductive layer 129 and the continuity in electrical charge between the connecting conductive layer 129 and an electrolyte layer 123, the electrolyte layer 123 is isolated from the connecting conductive layer 129 by insulating layers 125, 125 between devices. In addition, in FIG. 12, a reference numeral 122 denotes a porous semiconductor layer, and a reference numeral 124 denotes a catalyst layer.    Patent Document 1: Japanese Patent No. 2664194    Patent Document 2: Domestic Re-Publication of PCT International Application WO2002/052654 pamphlet    Patent Document 3: Published Japanese Translation of a PCT application No. 2005-516364    Patent Document 4: Japanese Unexamined Patent Publication No. 2001-357897